1. The Field of the Invention
The present invention relates generally to systems and methods for determining the authenticity of objects. More particularly, the present invention is related to systems and methods for automatically verifying the authenticity of an item by scanning for a security feature having predetermined spectral reflectance characteristics.
2. The Relevant Technology
In modern society, various conventional methods are utilized to trade goods and services. There are, however, various individuals or entities that wish to circumvent such methods by producing counterfeit goods or currency. In particular, counterfeiting of items such as monetary currency, banknotes, credit cards, and the like is a continual problem. The production of such items is constantly increasing and counterfeiters are becoming more sophisticated, particularly with the recent improvements in technologies such as color printing and copying. In light of this, individuals and business entities have a desire for improved ways to verify the authenticity of goods exchanged and/or currency received. Accordingly, the methods used to prevent counterfeiting through detection of counterfeit articles or objects must increase in sophistication.
Methods used to scan currency and other security items to verify their authenticity are described in U.S. Pat. Nos. 5,915,518 and 5,918,960 to Hopwood et al. The methods described in the Hopwood patents utilize ultraviolet (UV) electromagnetic radiation or light sources to detect counterfeit currency or objects. Generally, the tested object is illuminated by UV light and the resultant quantity of reflected UV light is measured by way of two or more photocells. The quantity of UV light reflected from the object is compared against the level of reflected UV light from a reference object. If the reflectance levels are congruent then the tested object is deemed authentic.
The methods in the Hopwood patents are based on the principle that genuine monetary notes are generally made from a specific formulation of unbleached paper, whereas counterfeit notes are generally made from bleached paper. Differentiation between bleached and unbleached paper can be made by viewing the paper under a source of UV radiation. The process of detection can be automated by placing the suspect documents on a scanning stage and utilizing optical detectors and a data analyzing device, with associated data processing circuitry, to measure and compare the detected levels of UV light reflected from the tested document.
Unfortunately, there are many problems with UV reflection and fluorescence detection systems, that result in inaccurate comparisons and invalidation of genuine banknotes. For example, if the suspect object or item has been washed, the object can pick up chemicals which fluoresce and may therefore appear to be counterfeit. As a result, each wrongly detected item must, therefore, be hand verified to prevent destruction of a genuine object.
Other conventional methods to detect counterfeit objects utilize magnetic detection of items which have been embossed or imprinted with magnetic inks, and/or image verification of images on the object. Unfortunately, magnetic inks are available to counterfeiters and can be easily applied to counterfeit objects, and image verification systems can be fooled by counterfeit currency made with color photocopiers or color printers, thereby reducing the effectiveness of these anti-counterfeiting approaches.
Other verification methods utilize the properties of magnetic detection to detect the electrical resistance of items which have been imprinted with certain transparent conductive compounds. These methods are, however, relatively complicated and require specialized equipment which is not easily available, maintainable, or convenient to operate, particularly for retail establishments or banks that wish to quickly verify the authenticity of an item.
Various items such as banknotes, currency, and credit cards have more recently been imprinted or embossed with optical interference devices such as optically variable inks or foils in order to prevent counterfeiting attempts. The optically variable inks and foils exhibit a color shift which varies with the viewing angle. While these optical interference devices have been effective in deterring counterfeiting, there is still a need for an accurate and convenient measuring system to verify that an item is imprinted with an authentic optical interference device.
With current advances in technology, new techniques are needed to battle a counterfeiter's ability to fabricate counterfeit objects. Accordingly, there is a need to provide authentication systems that extend the arsenal available to governments, business retailers, and banks to verify the authenticity of an item.